Building Science

71 Ways to Make Your Building More Energy Efficient

An ener­gy effi­cient build­ing reduces main­te­nance and util­i­ty costs, but, in many cas­es, improves dura­bil­i­ty, lessens noise, increas­es com­fort and cre­ates a healthy and safe indoor envi­ron­ment. A fur­ther goal of ener­gy effi­cient con­struc­tion is to lim­it dam­age to the ecosys­tem and reduce the use of nat­ur­al resources like ener­gy, land, water, and raw mate­ri­als. Reduc­ing ener­gy con­sump­tion is cru­cial because it means few­er emis­sions of green­house gas­es, a known cause of glob­al warm­ing. Ener­gy effi­cient mea­sures can be inte­grat­ed into new con­struc­tion or retro­fit­ted into an exist­ing build­ing. For­tu­nate­ly, there are many meth­ods, mate­ri­als, and resources to help design­ers, archi­tects, con­trac­tors and build­ing own­ers move towards cre­at­ing an ener­gy effi­cient and high-per­for­mance build­ing.

Energy Efficient Techniques in New Construction

New con­struc­tion gives archi­tects, con­trac­tors and build­ing own­ers the oppor­tu­ni­ty to design and build an ener­gy effi­cient build­ing, and even a net-zero ener­gy project. A net-zero ener­gy build­ing con­sumes less than or equal to the amount of ener­gy that it pro­duces on site through renew­able resources. The steps for con­struct­ing a mod­ern ener­gy effi­cient struc­ture begin with choos­ing a site and imple­ment­ing a detailed, holis­tic design plan.

Site Selection and Placement of an Energy Efficient Building

1. Ensure that pub­lic trans­porta­tion is avail­able and local shop­ping is near­by. Lim­it­ing trav­el time and the use of pri­vate trans­porta­tion will reduce wear and tear on vehi­cles and save gas.

2. Build near exist­ing infra­struc­ture to save mon­ey and resources.

Design of an Energy Efficient Building

3. Imple­ment­ing a whole-build­ing sys­tems approach to new con­struc­tion is the most effi­cient way to achieve an ener­gy effi­cient build­ing. The whole-build­ing approach treats the build­ing as one ener­gy sys­tem with sep­a­rate, but depen­dent parts. Each part affects the per­for­mance of the entire sys­tem (the whole-build­ing).

4. The design should make effi­cient use of water and elec­tric­i­ty and oth­er nat­ur­al resources and ener­gy sources.

5. To min­i­mize waste and mate­ri­als, choose the small­est pos­si­ble build­ing for the intend­ed appli­ca­tion.

6. The design should strive to meet the Ener­gy Star require­ments for sus­tain­abil­i­ty, the Lead­er­ship in Ener­gy and Envi­ron­men­tal Design (LEED) stan­dards, and the Inter­na­tion­al Green Con­struc­tion Code (IgCC).

7.The design of an ener­gy effi­cient build­ing should eas­i­ly allow for future retro­fits with­out impact­ing the per­for­mance of the build­ing.

8. The design should take into con­sid­er­a­tion build­ing ori­en­ta­tion. The way a struc­ture is sit­u­at­ed on a site and the place­ment of win­dows, rooflines and oth­er fea­tures is crit­i­cal for effi­cien­cy.

9. The design of an ener­gy effi­cient build­ing should be sus­tain­able. A sus­tain­able design aims to lessen deple­tion of crit­i­cal resources like land, water, ener­gy, and raw mate­ri­als. Sus­tain­able design of facil­i­ties and infra­struc­ture also averts the destruc­tion of the ecosys­tem.

10. Uti­liz­ing an ener­gy mod­el­ing soft­ware is an effec­tive way to esti­mate a build­ing’s ener­gy use. The mod­el’s out­put can help archi­tects, con­trac­tors, and build­ing own­ers mod­i­fy a build­ing per­for­mance and cost before con­struc­tion starts.

Wall Assembly of an Energy Efficient Building

11. A con­tin­u­ous lay­er of insu­la­tion (CI) around the build­ing enve­lope is essen­tial to an ener­gy effi­cient build­ing. Con­tin­u­ous insu­la­tion increas­es the effec­tive R‑value of the struc­ture, elim­i­nates con­den­sa­tion, and cre­ates a com­fort­able space for the building’s occu­pants. The Amer­i­can Soci­ety of Heat­ing, Refrig­er­at­ing and Air-Con­di­tion­ing Engi­neers (ASHRAE 90.1) and the Inter­na­tion­al Ener­gy Con­ser­va­tion Code (2015 IECC) also require con­tin­u­ous insu­la­tion in most appli­ca­tions.

12. For wood-framed con­struc­tion, pro­vide more space for insu­la­tion between inte­ri­or and exte­ri­or walls by uti­liz­ing 2X6 studs instead of 2X4 studs.

13. For wood-framed con­struc­tion, use a high-qual­i­ty insu­la­tion like spray foam insu­la­tion. Spray foam insu­la­tion can pro­vide an air bar­ri­er and is a far supe­ri­or insu­la­tion method over a less expen­sive insu­la­tion mate­r­i­al like batts and blan­kets.

14. Because tight­ly sealed, ener­gy-effi­cient, wood-frame build­ings are vul­ner­a­ble to mois­ture accu­mu­la­tion in the wall cav­i­ties, the exte­ri­or of the build­ing must be wrapped in a water-resis­tant and breath­able mate­r­i­al. Mois­ture in a build­ing’s walls is seri­ous because mois­ture can lead to wood rot (caused by fun­gi) and expen­sive repairs. Mois­ture may also cause the growth of mold, which is unhealthy to the occu­pants of the struc­ture. It is essen­tial that a wood-frame build­ing enve­lope con­trols mois­ture entry, accu­mu­la­tion, and removal.

15. An ener­gy effi­cient wood-framed build­ing uti­lizes advanced house fram­ing (also known as opti­mum val­ue engi­neer­ing). Advanced house fram­ing reduces lum­ber use and waste and improves the ener­gy effi­cien­cy of a wood-framed house.

16. Struc­tur­al insu­lat­ed pan­el (SIP) can save up to 50 per­cent in ener­gy costs. SIPs are made from a lay­er of foam insu­la­tion placed between pieces of ply­wood, strand board or cement pan­els.

17. To cre­ate an ener­gy effi­cient con­crete struc­ture, uti­lize con­crete wall sys­tems with inte­gral insu­la­tion made of expand­ed poly­styrene insu­la­tion (EPS) or oth­er insu­lat­ing foam. Insu­lat­ed con­crete forms and insu­lat­ed con­crete blocks form a lay­er of con­tin­u­ous insu­la­tion, sub­stan­tial­ly elim­i­nat­ing ther­mal bridg­ing through the wall. The Bau­tex Block Wall Sys­tem is an exam­ple of an insu­lat­ed con­crete block wall sys­tem that pro­vides a con­tin­u­ous insu­la­tion R‑value of 14, far exceed­ing 2015 IECC rec­om­men­da­tions.

18. For con­crete con­struc­tion, apply an air and mois­ture bar­ri­er to the exte­ri­or face of the con­crete wall. Ful­ly adhered mem­branes and flu­id applied air and mois­ture bar­ri­ers like the Bau­tex Air and Mois­ture Bar­ri­er work well with con­crete con­struc­tion. Air tight­ness of a build­ing has a sig­nif­i­cant pos­i­tive impact to over­all ener­gy effi­cien­cy.

Energy Efficient Techniques in Renovations and New Construction

An Energy Efficient Roof

An ener­gy effi­cient roof (cool roof) is designed to reflect sun­light and absorb less heat than a stan­dard roof. Cool roofs reduce ener­gy bills, improve indoor com­fort, and may extend the ser­vice life of the roof. There are sev­er­al tech­niques for cre­at­ing a cool roof.

19. Cool roof coat­ings have spe­cial reflec­tive pig­ments or are white to reflect sun­light. A light-col­ored roof absorbs less than 50 per­cent of the solar ener­gy, which reduces a roof’s tem­per­a­ture. In con­trast, dark roofs absorb 90 per­cent of the solar ener­gy.

20. Select­ing a cool roof is depen­dent on the slope of a roof. For low-sloped roofs, with a pitch of 9.5 degrees or less, choose sin­gle-ply mem­branes that are light-col­ored and reflect the sun. Sin­gle-ply mem­branes are pre-fab­ri­cat­ed sheets that are rolled onto the roof and con­nect­ed with mechan­i­cal fas­ten­ers, bond­ed with chem­i­cal adhe­sives, or kept in place with bal­last (stones, grav­el or pavers).

21. Paint­ed met­al roofs also sat­is­fy low-slope cool roof require­ments for solar reflectance.

22. For steep sloped cool roofs, choose shin­gles. Cool shin­gle roofs are over­lap­ping pan­els made from wood, asphalt, met­als, or poly­mers. The solar reflec­tive gran­ules that coat the shin­gles keep the roof cool.

23.For steep sloped cool roofs, tiles, made from con­crete, clay or slate, are also a good choice. Most tiles are nat­u­ral­ly reflec­tive; how­ev­er, treat­ments are avail­able for tiles that are not nat­u­ral­ly reflec­tive.

24. Green roofs are per­fect for urban build­ings with flat or shal­low-pit roofs. Green roofs include any­thing from basic plant cov­er to a work­ing gar­den.

Glazing Systems (windows, skylights, vents, and glass portions of doors) of an Energy Efficient Building

25. Pur­chase ener­gy effi­cient win­dows appro­pri­ate for your cli­mate zone.

26. Installing storm win­dows can low­er ener­gy bills by up to $350 a year.

27. In the north­ern hemi­sphere, face major glaz­ing areas south to take advan­tage of the solar heat gain in win­ter months when the sun is low.

28. For warmer cli­mates, lim­it south fac­ing glaz­ing and install over­hangs or oth­er shad­ing devices over the south fac­ing win­dows to pre­vent exces­sive heat gain dur­ing the sum­mer.

29. In the south­ern hemi­sphere, north-fac­ing win­dows are best.

30. Low-emis­siv­i­ty (low‑e) win­dow glaz­ing helps to con­trol solar heat loss and gains. In fact, com­put­er sim­u­la­tions indi­cate that advanced win­dow glaz­ing reduces the space cool­ing require­ments of new homes in warm cli­mates by more than 40 per­cent.

31. Choose ener­gy-effi­cient sky­lights that have estab­lished min­i­mum ENER­GY STAR® per­for­mance rat­ing cri­te­ria by cli­mate.

32. New exte­ri­or doors typ­i­cal­ly fit and insu­late bet­ter than old doors. When select­ing a new door, con­sid­er buy­ing the most ener­gy-effi­cient door pos­si­ble accord­ing to ener­gy per­for­mance rat­ings asso­ci­at­ed with the local cli­mate and the build­ing’s design.

33. If you plan to keep an exist­ing exte­ri­or door, a storm door is a good invest­ment.

34. Improve an exist­ing window’s ener­gy effi­cien­cy with caulk­ing and weath­er-strip­ping, and the use of ther­mal win­dow treat­ments or cov­er­ings.

Ventilation in an Energy-Efficient Building

Prop­er ven­ti­la­tion is nec­es­sary for an ener­gy-effi­cient home because air seal­ing tech­niques may trap pol­lu­tants (like formalde­hyde, volatile organ­ic com­pounds, and radon). Ven­ti­la­tion also helps con­trol mois­ture, which can cause mold growth and struc­tur­al dam­age.

35. An ener­gy effi­cient build­ing should include an ener­gy recov­ery ven­ti­la­tion sys­tem. An ener­gy recov­ery ven­ti­la­tion sys­tem pro­vides con­trolled ven­ti­la­tion and min­i­mizes ener­gy loss by trans­fer­ring ener­gy from con­di­tioned air going out to fresh incom­ing air.

36. Install local­ized exhaust fans above kitchen ranges and in bath­rooms to cre­ate spot ven­ti­la­tion. Spot ven­ti­la­tion improves the effec­tive­ness of nat­ur­al and whole-house ven­ti­la­tion by remov­ing indoor air pol­lu­tion and mois­ture.

37. While nat­ur­al ven­ti­la­tion is the least expen­sive and most ener­gy-effi­cient way to cool build­ings, it works best when com­bined with spot ven­ti­la­tion, ceil­ing fans, and win­dow fans. For large homes and build­ings, whole build­ings fans are a worth­while invest­ment.

Heating and Cooling Systems of an Energy Efficient Building

Cool­ing, heat­ing, and water heat­ing account for the largest ener­gy expens­es in homes and com­mer­cial build­ings. Incor­po­rat­ing ener­gy effi­cient mea­sures into a build­ing’s heat­ing and cool­ing sys­tems are essen­tial to cre­at­ing an ener­gy-effi­cient struc­ture.

38. Choose a high ener­gy effi­cient heat­ing, ven­ti­la­tion and air con­di­tion­ing (HVAC) sys­tem. For instance, the most effi­cient HVAC sys­tem is 95 per­cent effi­cient; mean­ing 5 per­cent of the ener­gy pro­duced is expelled. Con­sid­er replac­ing the HVAC every ten years.

39. Prop­er instal­la­tion of a new HVAC sys­tem is essen­tial to an ener­gy effi­cient build­ing. Improp­er­ly installed HVAC sys­tems can reduce a sys­tem’s effi­cien­cy by up to 30 per­cent.

40. Ensure that the fronts of vents are clear of obstruc­tions like fur­ni­ture and paper. Blocked vents require as much as 25 per­cent more ener­gy to dis­trib­ute air.

41. Install a pro­gram­ma­ble ther­mo­stat to man­age peri­ods of time where the heat­ing and cool­ing can be turned down and up.

42. Change the air fil­ter of the HVAC sys­tem as pre­scribed by the equip­ment man­u­fac­tur­er. Dirty fil­ters slow down air flow and make the sys­tem work hard­er to keep a build­ing warm or cool. Also, a clean fil­ter pre­vents dust and dirt from build­ing up in the sys­tem. Dust and dirt in an HVAC can lead to expen­sive main­te­nance and ear­ly sys­tem fail­ure.

43. Main­tain the HVAC annu­al­ly to ensure its high effi­cien­cy, longevi­ty, and the com­fort lev­el of the build­ing.

44. To main­tain an ener­gy effi­cient build­ing seal­ing the ducts that move air to-and-from the HVAC sys­tem is cru­cial. It is of par­tic­u­lar impor­tance to seal the ducts that run through the attic, crawl­space, unheat­ed base­ment, or garage. Seal the seams and con­nec­tions of ducts with sealant (mas­tic) or met­al-backed (foil) tape then wrap the ducts in insu­la­tion. The insu­la­tion will keep the ducts from get­ting cold in the win­ter and hot in the sum­mer.

High-Efficiency Water Heaters

Because heat­ing water accounts for about 7 per­cent of com­mer­cial build­ing ener­gy use and 15 per­cent of home ener­gy use, it is essen­tial, for a high-effi­cien­cy build­ing, to con­sid­er ener­gy effi­cien­cy when select­ing a water heat­ing sys­tem.

45. A tan­k­less water heater heats water just when need­ed, elim­i­nat­ing ener­gy lost dur­ing the stand­by oper­a­tion.

46. Install a high-effi­cien­cy stor­age (tank) water heater. High-effi­cien­cy water heaters use 10 to 50 per­cent less ener­gy than stan­dard mod­els, sav­ing ener­gy and mon­ey on util­i­ty bills.

47. A high-effi­cien­cy heat pump water heater trans­fers ener­gy from the sur­round­ing air to water in a stor­age tank. High-effi­cien­cy heat pump water heaters are most effec­tive in warm cli­mates with long cool­ing sea­sons.

48. A high-effi­cien­cy solar water heater can reduce oper­at­ing costs up to 90 per­cent.

Renewable Energy Sources for an Energy Efficient Building

49. Install grid-tied solar pho­to­volta­ic (PV) pan­els for a cost-effec­tive form of renew­able ener­gy. Solar pho­to­volta­ic can pow­er all the ener­gy needs of a build­ing includ­ing light­ing, heat­ing and cool­ing sys­tems, appli­ances and hot water.

50. Install a small wind sys­tem either con­nect­ed to the elec­tric grid through your pow­er provider or stand-alone (off-grid). A small wind elec­tric sys­tem can low­er elec­tric bill by 50 to 90 per­cent. A vari­ety of appli­ca­tions can use a small wind sys­tem, includ­ing water pumps.

51. A small hybrid” elec­tric sys­tem com­bines home wind elec­tric and home solar elec­tric (pho­to­volta­ic or PV) tech­nolo­gies. A hybrid sys­tem is best in regions where peak times for wind and solar sys­tems occur at dif­fer­ent peri­ods of the day and year.

52. On prop­er­ties with flow­ing water, Micro­hy­dropow­er is a sim­ple and con­sis­tent form of renew­able ener­gy. A micro­hy­dropow­er sys­tem requires a tur­bine, water wheel, and pump to trans­form the ener­gy of flow­ing water into rota­tion­al ener­gy, and then into elec­tric­i­ty.

Energy Efficient Lighting

53. Switch to light-emit­ting diode (LED) light bulbs. LED bulbs are ener­gy-effi­cient, durable, and long-last­ing.

54. Install con­trols such as timers and pho­to­cells that turn lights off when not in use. Dim­mers, when used to low­er light lev­els, also save mon­ey and ener­gy.

55. Use task light­ing where suit­able. A task light con­sumes far less ener­gy than a typ­i­cal over­head light­ing fix­ture.

Energy Efficient Appliances

56. Select ENER­GY STAR® refrig­er­a­tors because they use 15 per­cent less ener­gy than non-qual­i­fied mod­els. Also, refrig­er­a­tors with top-mount­ed freez­ers use 10 – 25 per­cent less ener­gy than side-by-side or bot­tom-mount units.

57. Select ENER­GY STAR® dish­wash­ers. ENER­GY STAR® dish­wash­ers use less water and ener­gy than required by fed­er­al stan­dards. Dish­wash­ers are cur­rent­ly required to use 4.25 gal­lons of water per cycle or less.

58. Select com­mer­cial con­vec­tion ovens that have earned the ENER­GY STAR® rat­ing. ENER­GY STAR® com­mer­cial ovens are about 20 per­cent more ener­gy effi­cient than stan­dard mod­els.

59. An auto­mat­ic elec­tric igni­tion sys­tem on a nat­ur­al gas oven or range can save gas because the pilot light is not con­tin­u­ous­ly burn­ing.

60. Mon­i­tor flame col­or of nat­ur­al gas ovens or ranges. A yel­low flame indi­cates the gas is not burn­ing effi­cient­ly and an adjust­ment is need­ed.

61. Keep ENER­GY STAR® range-top burn­ers and reflec­tors clean, so they will reflect the heat bet­ter and save ener­gy.

62. Select clothes wash­ers and dry­ers that have earned the ENER­GY STAR® rat­ing.

Energy Efficient Electronics, Computers, and Office Equipment

63. Whether work­ing in an office build­ing or from home, uti­liz­ing ener­gy effi­cient elec­tron­ics, com­put­ers, and office equip­ment can save build­ing own­ers ener­gy and mon­ey.

64. Pur­chase ENER­GY STAR®-labeled office equip­ment which can save as much as half the elec­tric­i­ty of stan­dard office equip­ment.

65. Use a lap­top com­put­er because lap­tops use much less ener­gy than desk­top com­put­ers.

66. Use sleep mode and pow­er man­age­ment fea­tures on the com­put­er.

67. Unplug elec­tron­ics when not in use because many elec­tron­ics con­tin­ue to draw a small amount of pow­er even when switched off. These lit­tle draws on ener­gy can occur on most appli­ances that use elec­tric­i­ty: DVD play­ers, TVs, stere­os, com­put­ers, bat­tery charg­ers, and kitchen appli­ances.

68. The U.S. Depart­ment of Ener­gy’s (DOE) rec­om­mends the fol­low­ing guide­lines for turn­ing off com­put­ers, mon­i­tors, print­ers, etc. to save ener­gy and mon­ey.

  • Turn off the mon­i­tor if not using the com­put­er for more than 20 min­utes.
  • Turn off both the CPU and mon­i­tor if not using the com­put­er for more than 2 hours.

Other Ways to Make a Building More Energy Efficient

69. Incor­po­rate ener­gy effi­cient land­scap­ing into the over­all build­ing design. For instance, shady land­scap­ing pro­tects a build­ing from direct sun­light dur­ing the sum­mer and allows more sun­light to reach through win­dows dur­ing the win­ter. Addi­tion­al­ly, plant­i­ng trees on the south­ern and west­ern side of a build­ing can keep the build­ing cool­er because it blocks sun­light from falling direct­ly on the build­ing dur­ing the win­ter; then, when after the trees lose their leaves, the trees allow more sun­light to reach the build­ing.

70. Opti­mize sys­tem con­trol strate­gies with occu­pan­cy sen­sors, CO2 sen­sors, and oth­er air qual­i­ty alarms.

71. Choose win­dow treat­ments or cov­er­ings not only for dec­o­ra­tion but also for sav­ing ener­gy. For exam­ple, triple lay­er cel­lu­lar shades can sig­nif­i­cant­ly reduce your util­i­ty bill and make the inte­ri­or of a build­ing more com­fort­able.

Conclusion

While the upfront costs of mak­ing a build­ing ener­gy effi­cient may seem high, build­ing own­ers soon recoup the extra cost through reduced util­i­ty and main­te­nance expens­es. Also, incor­po­rat­ing ener­gy effi­cient fea­tures into a build­ing make it more valu­able. In fact, a McGraw-Hill Con­struc­tion sur­vey report­ed that new green build­ing val­ues were 7 per­cent greater than new non-green build­ing projects. Green retro­fit build­ing val­ues were 5 per­cent greater than non-green retro­fit build­ings. Today’s ener­gy effi­cient tech­nol­o­gy is exten­sive and can be incor­po­rat­ed into all sizes and price ranges of new con­struc­tion and remod­el projects. Vis­it Bau­tex™ Wall Sys­tems for more ways to make a build­ing more ener­gy effi­cient.

Sources

Glob­al warm­ing refers to the mod­ern-day rise in glob­al tem­per­a­ture near the earth’s sur­face. The increase in tem­per­a­ture is due to increas­ing con­cen­tra­tions of green­house gas­es (car­bon diox­ide (CO2), methane (CH4), nitrous oxide (N2O), and flu­o­ri­nat­ed gas­es) in the atmos­phere. The expla­na­tion for glob­al warm­ing is straight­for­ward.

The sun’s ener­gy falls on the earth as ultra­vi­o­let, vis­i­ble (light), and infrared (heat) elec­tro­mag­net­ic ener­gy. The earth absorbs some of the sun’s ener­gy as ther­mal ener­gy. The earth reflects anoth­er part of the sun’s ener­gy (infrared heat) back into the atmos­phere where it either pass­es through the atmos­phere or is reflect­ed back to the earth’s sur­face. Nitro­gen and oxy­gen, which are the dom­i­nant gas­es in the atmos­phere, allow infrared heat to pass through the atmos­phere, while the green­house gas­es absorb infrared heat and redi­rect it back to the earth. The more green­house gas­es, the more heat is redi­rect­ed back to earth; hence the increase in glob­al tem­per­a­tures near the earth’s sur­face.

Accord­ing to the Nation­al Cli­mat­ic Data Cen­ter, before the Indus­tri­al Rev­o­lu­tion (about the year 1800), lev­els of car­bon diox­ide were about 280 parts per mil­lion by vol­ume (ppmv); cur­rent lev­els are greater than 380 ppmv and increas­ing at a rate of 1.9 ppm per year since 2000. The burn­ing of fos­sil fuels (coal, nat­ur­al gas, and oil), sol­id waste, trees and wood prod­ucts, and cer­tain chem­i­cal reac­tions (e.g., man­u­fac­ture of cement) are respon­si­ble for the increase in green­house gas­es. Fur­ther­more, because plants absorb CO2 (thus remove it from the atmos­phere) as part of their bio­log­i­cal car­bon cycle, defor­esta­tion and also lead to increased CO2 lev­els in the atmos­phere. Adverse impacts of glob­al warm­ing are exten­sive. A few of the impacts include ris­ing sea lev­els due to increas­ing rates of glacial melt­ing, more acidic oceans due to increas­ing car­bon diox­ide lev­els, and more fre­quent and severe weath­er events — like hur­ri­canes.